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<TITLE>FFmpeg FAQ</TITLE>
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<H1>FFmpeg FAQ</H1>
<P>
<P><HR><P>
<H1>Table of Contents</H1>
<UL>
<LI><A NAME="TOC1" HREF="faq.html#SEC1">1. General Problems</A>
<UL>
<LI><A NAME="TOC2" HREF="faq.html#SEC2">1.1 ffserver doesn't not work.</A>
<LI><A NAME="TOC3" HREF="faq.html#SEC3">1.2 I cannot read this file although this format seems to be suppored by ffmpeg.</A>
<LI><A NAME="TOC4" HREF="faq.html#SEC4">1.3 I get audio/video synchro problems when grabbing.</A>
<LI><A NAME="TOC5" HREF="faq.html#SEC5">1.4 How do I encode jpegs to another format ?</A>
<LI><A NAME="TOC6" HREF="faq.html#SEC6">1.5 FFmpeg does not support codec XXX. Can you include a Windows DLL loader to support it ?</A>
<LI><A NAME="TOC7" HREF="faq.html#SEC7">1.6 How can I read from the standard input or write to the standard output ?</A>
<LI><A NAME="TOC8" HREF="faq.html#SEC8">1.7 Why Audio is not decoded in VOB files ?</A>
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<LI><A NAME="TOC9" HREF="faq.html#SEC9">2. Development</A>
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<LI><A NAME="TOC10" HREF="faq.html#SEC10">2.1 Are there examples of use of the FFmpeg libraries libavcodec and libavformat ?</A>
<LI><A NAME="TOC11" HREF="faq.html#SEC11">2.2 Can you support my C compiler XXX ?</A>
<LI><A NAME="TOC12" HREF="faq.html#SEC12">2.3 Can I use FFmpeg or libavcodec under Windows ?</A>
<LI><A NAME="TOC13" HREF="faq.html#SEC13">2.4 Can you add automake, libtool or autoconf support ?</A>
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FFmpeg FAQ




<H1><A NAME="SEC1" HREF="faq.html#TOC1">1. General Problems</A></H1>



<H2><A NAME="SEC2" HREF="faq.html#TOC2">1.1 ffserver doesn't not work.</A></H2>

<P>
ffmpeg development is now concentrated on the codec and format
handling. New developments broke ffserver, so don't expect it to work
correctly. It is planned to fix it ASAP.




<H2><A NAME="SEC3" HREF="faq.html#TOC3">1.2 I cannot read this file although this format seems to be suppored by ffmpeg.</A></H2>

<P>
Even if ffmpeg can read the file format, it may not support all its
codecs. Please consult the supported codec list in the ffmpeg
documentation.




<H2><A NAME="SEC4" HREF="faq.html#TOC4">1.3 I get audio/video synchro problems when grabbing.</A></H2>

<P>
Currently, the grabbing stuff does not handle synchronisation
correctly. You are free to correct it. It is planned to fix it ASAP.




<H2><A NAME="SEC5" HREF="faq.html#TOC5">1.4 How do I encode jpegs to another format ?</A></H2>

<P>
If the jpegs are named img1.jpg, img2.jpg, img3.jpg,..., use:



<PRE>
  ffmpeg -i img%d.jpg /tmp/a.mpg
</PRE>

<P>
<SAMP>`%d'</SAMP> is replaced by the image number.


<P>
<TT>`img%03d.jpg'</TT> generates <TT>`img001.jpg'</TT>, <TT>`img002.jpg'</TT>, etc...


<P>
The same system is used for the other image formats.




<H2><A NAME="SEC6" HREF="faq.html#TOC6">1.5 FFmpeg does not support codec XXX. Can you include a Windows DLL loader to support it ?</A></H2>

<P>
No. FFmpeg only supports open source codecs. Windows DLLs are not
portable, bloated and often slow.




<H2><A NAME="SEC7" HREF="faq.html#TOC7">1.6 How can I read from the standard input or write to the standard output ?</A></H2>

<P>
Use <TT>`-'</TT> as filename.




<H2><A NAME="SEC8" HREF="faq.html#TOC8">1.7 Why Audio is not decoded in VOB files ?</A></H2>

<P>
AC3 decoding is optional as the codec is currently released under the
GPL. Enable it with <CODE>./configure --enable-a52</CODE>. Take care: by
enabling AC3, you automatically change the license of libavcodec from
LGPL to GPL.




<H1><A NAME="SEC9" HREF="faq.html#TOC9">2. Development</A></H1>



<H2><A NAME="SEC10" HREF="faq.html#TOC10">2.1 Are there examples of use of the FFmpeg libraries libavcodec and libavformat ?</A></H2>

<P>
Yes. Read the Developers Guide of the FFmpeg documentation.




<H2><A NAME="SEC11" HREF="faq.html#TOC11">2.2 Can you support my C compiler XXX ?</A></H2>

<P>
No. Only GCC is supported. GCC is ported on most systems available and I
don't see the need to pollute the source code with <CODE>#ifdef</CODE>s
related to the compiler.




<H2><A NAME="SEC12" HREF="faq.html#TOC12">2.3 Can I use FFmpeg or libavcodec under Windows ?</A></H2>

<P>
Yes, but the MinGW tools <EM>must</EM> be used to compile FFmpeg. You
can link the resulting DLLs with any other Windows program. Read the
<EM>Native Windows Compilation</EM> section in the FFmpeg documentation
to have more information.




<H2><A NAME="SEC13" HREF="faq.html#TOC13">2.4 Can you add automake, libtool or autoconf support ?</A></H2>

<P>
No. These tools are too blowted and they complicate the build. Moreover,
since only <SAMP>`gcc'</SAMP> is supported they would add little advantages in
terms of portability.


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